Darpa kills shape-shifting bomber

[Bluehawk]

The twilight zone...

Source and video link:
Darpa Kills Shape-Shifting, Supersonic Bomber | Danger Room from Wired.com
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The Pentagon's shape-shifting, sideways-flying, unmanned, supersonic bomber program is coming to an end.

The Oblique Flying Wing, or "Switchblade," project was meant to produce an experimental aircraft that could travel 2,500 miles, loiter just outside enemy territory for more than a dozen hours and then attack at twice the speed of sound. It was never going to be an easy job; aircraft that do well at subsonic flight are inefficient at Mach speeds, and vice versa. But Darpa gave Northrop Grumman more than $10 million to come up with up designs that might work. The key: Make sure the plan was a shape-changer.

Switchblade would cruise along in a more-or-less standard configuration - with a 200-foot-long wing perpendicular to its engines. But just before the craft breaks the sound barrier, its single wing would swivel around 60 degrees so that one end points forward and the other back. This oblique configuration redistributes the shock waves that pile up in front of a plane at Mach speeds and cause drag. When the Switchblade returns to subsonic speeds, the wing would rotate back to perpendicular.

But someone would actually have to build the thing first. After "more than 1,000 subsonic and supersonic test runs" on the design, Aviation Week reports, Darpa has decided not to go ahead with an actual flight demonstrator. The program "has concluded following the preliminary design effort."
It's the latest in a series of blows for the Defense Department's premiere research agency. A few months ago, the Pentagon brass took away more than $130 million from its current budget. In September, Congress wiped out funding for "Blackswift," Darpa's program to develop a hypersonic plane. Then the Senate and the House agreed to blast tens of millions of dollars from Darpa's 2009 budget, citing "poor execution."

Back in 1945, engineers theorized that a plane with oblique wings – one angled forward, the other pointing back – would meet less resistance at Mach speeds. The cockeyed design would, in effect, give the plane a longer, thinner profile as it shot through the air. Sure, that meant the plane would be, in effect, flying sideways. But the air flowing around the plane, helping keep it aloft, would be much the same.

That didn't mean the jet would be easy to fly, though. Before it went supersonic, the wide wingspan would actually produce more drag. Plus, the lobsided design meant that every time a pilot pulls the nose up, the plane would roll to one side.

What was needed was a plane that could fly normally at first – and then transform once it broke the sound barrier. Until recently, though, there weren't smart enough computers to make the switch. (Or to help the pilots guide the new-jack plane.)

Not even Space Ship One designer Burt Rutan could make his version of an oblique-winged plane work. "We just didn't have the flight control systems and computer stability augmentations," Ilan Kroo, a Stanford aeronautics professor who worked on Rutan's project, told me.

The hope was that Switchblade could finally answer those decades-old questions, with the advent of advanced artificial intelligence software and fly-by-wire technology, which replaces a pilot's physical controls over an aircraft with computer code. The hope still remains unfulfilled.